Telecommunications has been among the fastest growing technologies of this century. Communication devices such as cell phones, PDAs, mobile televisions, personal navigation devices, personal media players, and a myriad others are becoming increasingly commonplace in modern society. Accordingly, the performance requirements of communications systems are increasing at a staggering pace. Today, these devices are under pressure to perform reliably and offer vast capabilities while maintaining a competitive price point.
The receiver is a critical component in a communication device's performance and cost. The receiver's function is to receive an often significantly distorted and attenuated signal and convert it into a signal that can be used by other components in the system. The quality of the signals produced by the receiver is a limiting factor in the performance of communications systems and manufacturers continuously strive to improve this aspect of receiver design.
One of the functions of the receiver is to amplify an incoming signal such that the gain of the signal is appropriate for other components in the system. However, the power of signals received at a receiver can vary significantly. Namely, due to attenuation, a signal's power declines as the signal travels away from the transmitter. For example, a signal sent to a receiver through the air may have significantly lower power further from the transmitter than close to it. The difference in power can be in the order of several magnitudes. Hence, a device in a traveling vehicle, for instance, may observe severe fluctuation in incoming signal power as it travels from the proximity of one radio tower into the proximity of another radio tower. As a result, the receiver must be able to amplify incoming signals in a broad power range to produce signals with desired gain and other desirable characteristics.
Existing devices apply a single amplification routine to all incoming signals. However, such systems result in a trade-off between signal noise and distortion with weak incoming signals producing noise and strong incoming signals producing distortion. What is needed is an RF receiver that processes incoming signals in a broad range of power and minimizes noise and distortion for signals across the range. As will be demonstrated, this invention performs this in an elegant manner.